Media ratings and metering information is typically generated by collecting viewing records and/or other media consumption information from a group of statistically selected households. Each of the statistically selected households typically has a data logging and processing unit commonly referred to as a “home unit.” In households having multiple viewing sites (e.g., multiple television systems or, more generally, multiple presentation devices), the data logging and processing functionality may be distributed among a single home unit and multiple “site units,” one site unit for each viewing site. The home unit (or the combination of the home unit and the site unit) is often in communication with a variety of attachments that provide inputs to the home unit or receive outputs from the metering unit. For example, a frequency detector attachment coupled with the home unit may be in communication with a television to sense a local oscillator frequency of the television tuner. In this manner, the frequency detector attachment may be used by the home unit to determine the channel to which the television is currently tuned based on a detected frequency. As another example, a people meter may be located in the viewing space of the television and in communication with the home unit, thereby enabling the home unit to detect the identities and/or number of the persons currently viewing programs displayed on the television. Additional devices may be provided, for example, to determine if the television is operating (i.e., is turned ON) and/or the channel to which the television is tuned.
In addition, building security and building monitoring systems are becoming more and more prevalent in today's society. Such systems enable the building owner to determine the status of various electronic appliances disposed in the building even when the building owner is located remotely from the building premises. In many instances, the building owner may desire to know the operating status, e.g., ON/OFF, of a particular appliance, such as a television, or other media delivery/presentation device.
In another setting, parents often have an interest in monitoring their children's television viewing habits, electronic gaming habits and computer usage habits. A component of monitoring such habits involves determining the operating status of the appliance, electronic device, etc. of interest.
Media monitoring systems, building monitoring systems and parenting tools such as those described above, are only three (of many) applications in which an ON/OFF detection apparatus/device has use.